Hi, I have a 1.5 y/o leopard tortoise and no matter how hard I try to trap heat in his enclosure I can’t seem to get his enclosure warm enough at night. I live in a colder state and cannot keep him outside and when it gets cold out there is a draft that I can’t control. His enclosure is basically completely sealed except for the area where his daytime lights go. What should I do to trap/ create more heat at night? Should I get another dome with a darker colored light for nighttime?